Manufacture of ceramic products.



, of much less from warping MANUFACTURE OF Specification of Letters Patent. Application filed April 4-, 1906. Serial No 309,904.

CERAMIC .PBQDUCTS I To all whom it may concern.-

Be it known that 1, MAX BUCHNER, a citizen of the Empire of Germany, residing at Mannheim, in the Empire of Germany, have invented certain new and useful Improvements in the Manufacture of Ceramic Prodnets; and I do hereby declare the following to be a full, clear, and exact description of the invent-ion, such as will enable others skilled in the art to which it appertains to make and use the same.

Ordinary siliceous ceramic materials containing silica and silicates, such as sand, quartz and the various clays, undergo variable and indefinite changes in volume in firing in the kiln, an object made of such materials not having the same size or relative dimensions before'and after firing and undergoing other changes with every successive tiring. This property is the source of much inconvenience in endeavoring to make articles of exact dimensions, and also the source and change of shape, expansion and contraction not always being equal in all directions. Quart-z has a tendency to swell in the fire while pure clays usually contract, but these tendencies cannot lie balanced very successfully by admixing sipce such mixtures do not have the expected intermediate properties, a fact probably due to i'nole'cular- ';a11cl chemical rearrangement of silicates in firing and re-firing. Expansion and contraction are uncertain quantities.

have discovered that fused. alumina is exempt from this annoying variability and on this fact based the process of making ceramic wares for which I have received United States Letters-Patent No. 700,673, May 20,1902. I have now discovered that similar valuable properties are possessed by-fused aluminates such as are prepared by dissolving metallic oxids in fused alumina; certain of these aluminates being like the alumina itself invariable in volume in the porcelain kiln and others expandin and contracting definitely, making them va uable additions to ordinary ceramic materials. They are also valuable because of the extreme resistance offered by fused alumina to attack by chemical reagents, a resistance shared by the aluminates', making the new ceramic bodies useful f or chemical apparatus and similar purposes. These new bodies may the desired oxid to the molten alumina; or

ing natural or artificial alumina and adding litatented lllay 14,

by mixing alumina with the oxids and fusing the mixture.

When the oxids are mixed in molecular proportions, the product is probably a true aluminate; when alumina or the oxid is in excess, a solid solution of the excess'ancl the true aluminate is prob ably formed. For the sake of convenience in nomenclature, the

' products are hereinafter 'called aluminates irrespective of the particular proportions of alumina and other oxid. The products differ in color and physical properties with the nature of the oxid combined with the alumina. For instance an aluminate containing iron oxid has the property of expanding slightly in firing; one containing chromium oxid, containing chromium oxid are very indifferent to heat, sudden changes chemical reagents and the like. Aluminates containing titanium oxid, magnesia, baryta, etc,, have slightly properties.

The basic oxids used with'the alumina to form aluminates may be employed singly or in mixture, and the proportions may be contracts slightly. Thosein temperature,-

different but valuable varied,- obtaining products of any desired I nature or properties. On incorporating such products with clay, kaolin and the like, plastic masses may be obtained which when fired in the usual way yield ceramic articles of excellent properties. of the articles ma be regulated to any desired degree, whicli for articles. to be glazed. or to be of exact size is of great importance. In using the new bodies they may besimply mixed with the desired amount of 0t 'er plastic ceramic material and water, molded or otherwise formed and fired in the usual av. I

Having't'hus fully described the invention,

Changes in volume I what I claim as new and desire to secure by Letters-Patent of the United States, is

1. The process of making ceramic ware which consists in fusing together alumina and an oxid in proportions to form an aluminate, converting the fused aluminate into a shaped plastic mass and firing said mass.

2. As a new ceramic composition, a fused aluminate of a metallic oxid.

be prepared by melt- 3. The process of making ceramic articles which consists in mixing a fused alun iirigte 6. As a new article of manufacture, a IO with a plastic. material and hung the; In? 1 ceramic article comprising nfused aluminate ture. i

and a clay, fired together. 4. The process 01' making ceramic uriiipics i In testimony wlicrcuf l hcrcunto affix my -5 which consists in mixing a fused aluminate 1 signature in the presence of two Witnesses. with a clay and firing the mixture. MAX BUCHNER.

5. As a new article of manufactur, a Witnesses: ceramic article comprising a fused aluminatcj 11. W. HARRIS,

and a plastic material, fired together. 1 Joss. H. LEUTE. 

